Question

Rick's automotive chaRges $50 plus $15 for each (15mins) unit of time when making a road call. Twin city repair charges $70 plus $10 for each unit of time. Under what circumstance would it be more economical for a motorist to call Rick's

Answer 1

let x is a 15 minute unit of time

RA = 50 + 15 x

TCR = 70 + 10 x

we need to know , when is

50 + 15x < 70 + 10 x
5x < 20
x < 4

so when ever the job is less than 4 times 15 minute units (or when the expected time is less than 1 hour)